In industries with high hygienic requirements, for example the food industry, the processing systems must be cleaned on a regular basis.
In a first phase of the cleaning, the processing system is rinsed with water, lye and acid, wherein lye and acid can be in a temperature range between 60° C. and 95° C. A sufficiently large fluid throughput is sought in all system parts. In this phase, it is referred to as CIP, “cleaning in place.”
In a second phase of the cleaning, the processing system is sterilized, which is referred to as SIP, “sterilization in place.” Reduced use of sterilizing chemicals is sought. Water steam is used, which is directed through the processing system under defined pressure and temperature conditions as saturated steam, for example, in a temperature range of 125° C. to 145° C. at a pressure of 2.3 bar to 3.1 bar. These conditions must be followed precisely. However, this is made more difficult because the processing system itself has a temperature distribution. For example, the processing system has cold sections where the condensation of steam results.
This condensate in the processing system is problematic for the sterilization process. The total energy demand increases through the condensate because the condensate must again be heated above the boiling point and/or new steam must be created to replace the condensed steam. The processing system, therefore, may not be freed of contaminants, e.g. bacteria in the area of the condensate. Thus, the condensate must be removed from the processing system with the help of a condensate drain.
German Patent No. DE 689 860 introduces a condensate drain for the chemical industry. It comprises a closing arrangement, which works together with an expansion body, which has a bellows. The bellows is filled with an easily boiling liquid. Through the heating via the bellows and the cover, gas and liquid expand, whereby the bellows expands in its axial direction. A closing cone is brought into sealing contact with a valve seat. If there is condensate in the condensate drain, the bellows is cooled so that gas and liquid contract in its interior. As a result, the bellows also contracts so that the closing member is raised from the valve seat and the condensate can flow out of the condensate drain.
German Patent Application No. DE 10 211 050 955 A1 shows a newer approach. In the condensate drain, the expansion body is completely foregone. In its place, the closing member is shifted by a pneumatic drive. The drive is driven by a control electronics, which reacts to temperature measurement values, which are raised in the interior of the condensate drain.